The Will to Disaster
The Will to Disaster R.Ramesh MoE&F's amnesia on the post tsunami technical feasibility of the Sethusamudram Shipping Canal Project The conditional clearance given for SSCP 1 by the Ministry of Environment and Forests (MoE&F) recently has totally ignored the post tsunami debate 2 on the technical feasibility of the canal. This article argues that such an attitude by MoE&F is bound to have long-term serious negative repercussions on the future economic, legal, ecological and social spaces of not only India but also of Sri Lanka. The warning came from none other than Dr.Tad.S.Murty. Dr.Murty is an expatriate Indian who had served as the chief editor of the reputed International Tsunami Journal “Science of Tsunami Hazards” for over two decades. He is considered as one of the leading scientists on tsunami in general and on the tsunamis of the Indian Ocean in particular. The PMO had invited him late this January for knowing his views on the establishment of the tsunami warning system for India. As he finished his briefing on the tsunami warning system for India he had something else also to share with the PMO: that was on the proposed alignment of the SSCP with respect to tsunamis that the Indian east coast might be subjected to in the future. “I like this (Sethusamudram) project’, he said, ‘but there is a flaw. The entrance to the channel should be re-oriented towards the eastern side. Otherwise, there is a chance that it may create a deepwater route for another devastating tsunami. This may cause huge destruction in Kerala.” 3 PMO had asked the Ministry of Shipping and Surface Transport (MSST) for a clarification on this question in mid February. Tuticorin Port Trust (TPT) who is the proponent of the canal submitted its answer on 28 February. MSST submitted its answer to the PMO on 4 March 4. However, on 8 March PMO had released an unofficial note (probably based on two articles on this issue published by EPW and CURRENT SCIENCE, 2 and on the opinion expressed in the press on this issue by the world renown paleao-seismologist Dr.C.P.Rajendran of CESS, Trivandrum) 5 to the press where it had raised a number of questions related with the technical feasibility of the canal. In this note, PMO had in particular questioned the ability of the proposed canal to withstand future tsunamis and cyclones 2. The Chief Minister of Tamil Nadu had also echoed this note in her statement released on 29 March 2. However, Mr.T.R.Balu, the minister for Shipping had denied such a note having been sent to his ministry by the PMO and since there is no further communication from the PMO to his ministry after the first note, he said the issue of doubts on the technical feasibility of SSCP is once for all settled4. He however did not consider clarifying as to why the very director of National Environmental Engineering Research Institute (NEERI), (that did the Environmental Impact Assessment (EIA) of the canal) had agreed in the public domain that the EIA done by his institute had not considered the issue of sedimentation 6 and the issue of tsunami. Tamil Nadu Pollution Control Board (TNPCB) had sent its report on SSCP late March. On receiving this report, MoE&F issued its clearance for the project immediately in the first week of April 7 The clearance, strangely, had not considered post tsunami debate on the technical feasibility of the canal and the acceptance by the director of NEERI himself that the EIA done by his institute had not considered the issues of sedimentation and tsunami and thus by implication that the study was incomplete. Also, it had also not considered it necessary to analyze the project's feasibility in the light of the various proposals put forward by the "National Workshop on Formulation of Science Plan for “Coastal Hazard Preparedness” conducted by National Institute of Oceanography, Goa on 18 - 19 February 2005 8. MoE&F's clearance has now allowed the SSCP to be placed in front of the Planning Commission and the Cabinet Committe for its final approval. The approval, it is said, is expected in another four weeks time (that is middle of May) 9. This article attempts a thorough scientific analysis of this issue of technical feasibility of the canal at the present time and the possible consequences of the Planning Commission and Cabinet Committee clearing the project without mustering clear, transparent answers from the project proponents for all the questions raised so far by experts in India and abroad. SSCP Physiography SSCP is an offshore shipping canal project in the Palk Bay. It plans to cut-short the distance navigated by ships originating from the west coast and bound for ports in the Indian east coast by avoiding circumnavigation of Sri Lanka. Ships would navigate through the Gulf of Mannar and Palk Bay and enter the Bay of Bengal directly. Dredging the shallow seabed of the Palk Bay and Adam's Bridge to a depth of 12 meters in order to make navigation possible for ships drawing a draught of 9.15 or 10.7 meters is the central idea of the project. The canal’s width would be 300 meters. The total length of the canal in the Palk Bay is 152.2 kilometers. This is divided into three legs; the southern leg in the Adam’s Bridge area is 20 km, the northern leg in the Palk Strait area is 54.2 km and the central portion is 78 km in length. Dredging would be done in the southern and northern legs; the central leg does not require dredging as it has the adequate depth of 12 meters. Navigation channels have so far been dredged in the East Coast of India only near the shipping ports. This probably is the first effort by India to dredge a navigation channel that is to be located 30 to 40 km away from the coast. This, again, is the longest seabed-dredging project planned so far in India. Modeling Studies on the December 26th Tsunami Dr.Tad.S.Murty's observation on SSCP is based on an in depth analysis of the various computer models proposed by tsunami experts around the world. There are nine models available so far. All of them are available in the Internet and are freely downloadable. They are: 1.Vasily Titov of the Pacific Marine Environmental Laboratory (PMEL) at NOAA, USA http://www.noaanews.noaa.gov/stories2004/s2357.htm, 2.Kenji Satake-National Institute of Advanced Industrial Science & Technology - Japan http://staff.aist.go.jp/kenji.satake/animation.gif, 3. DHI Software Company-USA http://www.dhisoftware.com/general/News/Tsunami/index.htm, 4.Baird Softwares-USA http://www.baird.com, 5. Steven N.Ward - University of California, http://www.es.ucsc.edu/~ward/ 6.NIO-Goa, http://www.nio.org 7.Aditya Riyadi of Pusat Penelitian Kelautan Institut Teknologi, Bandung, Indonesia http://www.ppk.itb.ac.id/aceh/simulasi-IV-2/simulasiIV-2.htm, 8.A.Pitanesi (INGV, Roma, Italia), 9. A.Yalciner, U.Kuran, T.Taymaz (Turkey) http://yalciner.ce.metu.edu.tr/sumatra/max-elev-sim-1.jpg All the nine models agree on one issue- namely the increased wave heights experienced by the stretch extending between Hambantota on the southern tip of Sri Lanka to Palar Estuary located 70 km south of Chennai. This stretch includes the east coast of Sri Lanka, the whole of Palk Strait, the coastal stretch between Kodiakkarai to Palar Estuary. Out of these nine models, the models proposed by Prof.Steven N.Ward, Aditya, and DHI Softwares give a clear visual picture of the wave patterns experienced by Palk Bay during the December 26th tsunami. The First Tsunami Wave, Palk Bay and SSCP Steven N.Ward's 'Peak Tsunami (wave) envelope height' animation model gives us the following important information. The first tsunami wave envelope embraces the continental shelf break of the Palk Strait at 1 hour 54 minutes after the time of onset December 26th Tsunamigenic earthquake (i.e. 6.29 am IST). This is 8.23 a.m IST. The wave height at this time is equal to or less than 0.5 meters. At 8.43 a.m the wave flows over the tabletop-like flat continental shelf of Palk Strait and reaches the stretch between Point Pedro of Sri Lanka and Nagapattinam of India 10. We note here that the wave has touched the northeastern tip of SSC's northern leg. The wave height at this time is between 1 to 1.5 meters. At 9.13 a.m the wave has reached the imaginary line drawn between Kankesanthurai and Vedaranyam. We note here that the wave now has embraced the northeastern tip of SSC for about 20 km. The wave height is now 1 to more than 3.5 meters. At 9.29 am, the wave has increased its height uniformly to around 3 to more than 3.5 meters and the wave has touched Kodiakkarai. By now, half of the northern leg of SSC has come under the tsunami wave. The wave entering the Palk Bay from Gulf of Mannar (located in the south), has just touched the southern leg (that is the Adam's Bridge portion) of the SSC. The wave height in this southern portion is from 0.5 to 1 meters at this time. From 9.30 am to 10.13 am the wave embraces the whole northern leg of SSC and also the coastal stretch between Kodiakkarai and Rajamadam. The wave height in this stretch at this time interval is between 0.5 to 1.5 meters. It is to be noted at this point of time, the wave prefers to enter the Palk Bay through the northern half of Palk Strait rather than the southern half of the Strait. In the Adams Bridge area, we note that the wave prefers to enter the Bay through the eastern half of the Bridge. At 10.23 am, we note that around 10 km of the southern tip of the 20 km long Adam's Bridge portion of the SSC has been occupied by a wave of 0.5 to 1.5 meter height. In the Palk Strait area the wave has encircled the northern tip of Sri Lanka and has embraced Manamelkudi, a spot known to be experiencing high sedimentation rates. We note at this point of time that around 20 km length of the middle 78 km of un-dredged portion of SSC embraced by a wave of 0.5 to 1.5 meter height. We see by 10.29 am (that is 4 hours from the onset of tsunami) the whole of Adam's Bridge portion of the SSC embraced by a wave of 0.5 to 1.5 meter tsunami wave, and half of the northern leg embraced by a wave of more than 3.5 meters height, and its remaining half and 20 km of the central un-dredged portion of the canal embraced by a 0.5 to 1.5 meter wave. Aditya's model agrees with Steven N.Ward's model in every detail, but shows the movement of waves still more clearly. Both these models agree with the wave travel time model created by Vasily Titov of PMEL. The model by DHI Software, however, differs by about half an hour from the above models. The first wave of DHI is late by half an hour to reach the above-mentioned points. As for the pattern of movement of the waves, DHI's model agrees with that of the other models. It will be of some importance to note here that the wave travel time model proposed by Vasily Titov is in conformity with Kenji Satake's animation model of the December 26th tsunami. Kenji's model had been confirmed correct by the JASON-1 Satellite imagery generatated during the tsunami itself. The average speed of the tsunami wave in the deep sea has been calculated to be around 600 to 650 km per hour. However, the speed with which it had moved into Palk Strait is astonishingly slow. It works out to be just 30 km per hour. For Nagapattinam it is around 200 km per hour 11. It is this point that had worried Dr.T.S.Murty, when he said, "the entrance to the channel should be re-oriented towards (i.e., in) the eastern side. Otherwise, there is a chance that it may create a deepwater route for another devastating tsunami. This may cause huge destruction in Kerala.” By Kerala, he had actually meant the entire shoreline extending from Dhanushkodi to Ernakulam. The steeply placed Palk Bay 10, it may be inferred from his statement, has actually shielded the above said shoreline from the harsh impact of the tsunami waves approaching it from the northeast direction1 11. Post tsunami field surveys Post tsunami field surveys undertaken in the south east coast of India Bay by various teams had revealed many interesting facts. "A team of scientists led by Dr V J Loveson of the Central Mining Research Institute (CMRI), Dhanbad, has been monitoring the level of placer deposits on Tamil Nadu's coastline since mid 2003. The team had said huge deposits of Titanium had been deposited on the shores from Vedaranyam to Cuddalore stretch by the December 26th tsunami. They have speculated something like 40 million tonnes of Titanium to have been deposited in the whole 500 kilo meters stretch of the coastline that was hit by the tsunami. " 12. Let us note here that the north-eastern tip of SSC is located just 35 km south of Vedaranyam. Post tsunami survey to detect tsunami wave run-up was conducted by Dr.Senthil Kumaran 13 from Jan 15 to Jan 30, 2005. The survey covered the entire coastline from Ernakulam to Chennai. The survey had revealed some important facts: The wave arrival time narrated by the people interviewed at Kodiakkarai coincided exactly with that of the wave arrival time indicated by the model proposed by Vasily Titov. "The shore line of Palk Bay stretching from Muthupet to Pamban had not experienced much damage from tsunami. However, the shoreline showed some distinct features. Unlike the shore lines in other areas, this shoreline in its entirity was dumped with heaps and heaps of uprooted seagrasses." The preliminary tsunami impact assessment report prepared by the Zoological Survey of India for none other than MoE&F has made the following remarks: “ The seaweed and sea grass ecosystem between Rameshwaram and Kanyakumari have either been uprooted or submerged, ‘dislocating many associated organisms and changing the species composition’. The worst affected is the benthic ecosystem comprising the invertebrate animals. A huge population of sponges has been affected and animals such as crabs, lobsters and stomatopods displaced from their coral homes. The tsunami has changed the breeding area by dumping silt and debris and relocating the breeding population to other areas which may not be conducive to their survival. Also, increased water turbidity may lead to mass mortality of fish. The breeding cycle of marine turtles have already been affected and the loss of the sea grass which is the main food for the endangered mammals like the dugong may also lead to a change in breeding habitat’.” 14 These observations indicate the following: 1) The computer model of Vasily Titov should be considered objective, 2) the near shore continental shelf regions of Vedaranyam - Nagapattinam area have faced excessive sedimentation, 2) Palk Bay has experienced an event which has caused a total decimation of the sea grass bed of the bay. Palk Bay has impeded the wave propagation considerably and hence the amount of sedimentation here should have been much higher than at the Vedaranyam - Cuddalore stretch. That the geomorphology of Palk Bay provides a conducive environment for excessive sedimentation is an established fact even before the current tsunami. The large scale uprooting of sea grasses in Palk Bay should have been due to the excessive turbulence experienced by the bay during tsunami. The bay had experienced waves both from north and south. Such events had been noted in the bay earlier and 1964 cyclone is one such event. Following this event, it had been noted, that the sea cows (dugongs) inhabiting the bay and thriving on the sea grasses, had disappeared for almost two decades. They had returned to the bay again only in the late eighties. 15 Lessons and Questions The foregoing discussion indicate to us three major points: 1. The presently proposed alignment of the northern leg of the canal might serve as a deep-water conduit to future tsunamis thus increasing the degree of tsunami risk to the coastal stretch extending from Dhanushkodi to Ernakulam. 2. Tsunami causes excessive sedimentation in the Palk Strait and Palk Bay. 3. Tsunamis and cyclones cause excessive turbulence in the bay thus causing extensive damage to the sea grass bed of the bay. These points lead us to the following questions: 1. What would have been the effect of excessive sedimentation on the structure of the canal and on the stability of its dredge dumps? 2. What would have been the effect of increased turbulence experienced by the bay during tsunami on the structure of the canal and on the stability of its dredge dumps? 3. What would have been the extent of damage to the shorelines of Sri Lanka and India located south of Talai Mannar and Dhanushkodi had the canal been operational at the time of the December 26th tsunami? Finding definitive answers to these questions are a must for ensuring the future stability of the canal and the shorelines around. However TPT, MSST, and MoE&F have not felt it necessary to consider or answer these questions. It is strange as to why the MoE&F was not willing even to wait for the report of the preliminary study it had commissioned to the Zoological Survey of India on the effect of tsunami on the marine ecology of Bay of Bengal! Implication of the post tsunami findings on the pre tsunami studies on Plak Bay Pre-tsunami studies on Palk Bay have indicated some specific pertinent issues related to Palk Bay. They are: 1.Palk Bay is a shallow sea located on a continental shelf region whose average depth is just 6 to 10 meters. Depth of Bay of Bengal located in the northeast is 2000 meters, and depth of Gulf of Mannar located south is 500 to 1000 meters. 2. It is one among the five major sediment sinks of India. In its capacity as a major sediment sink, it is responsible for maintaining the stability of the shorelines around 16. 3. Even though Palk Bay is a unique geographical locale, it is made up of many micro regions that differ from each other by the amount of sedimentation they experience. Some areas experience very high rates of sedimentation than other areas. Incidentally, the two legs of SSC that are to be dredged fall in areas of higher rates of sedimentation 17. 4. Palk Bay is an area identified as highly prone to tropical cyclones. They have caused large-scale damages in this area in the past. Out of the 61 cyclones that have crossed the Tamil Nadu coast in the period between 1891-1995 A.D., 6 have directly crossed the Palk Bay; 14 have crossed the Nagapattinam coast; 3 have crossed the Gulf of Mannar. Based on the storm surge values (3 to 5 meters), India Meteorological Department considers the coastal stretch between Nagapattinam and Pamban as a High Risk Zone to tropical cyclones 17. The 1964 December 23 cyclone had produced a storm surge of 6 meters 18. Based on the degree of uncertainty in the prior prediction of cyclones Sutapa Chaudary et al (2004) have named this coastal stretch (and that of Bangladesh) as the most vulnerable ones among the many coastal regions of the Bay of Bengal, for Severe Tropical Cyclones 19. 5. It has been identified that the sediments have a tendency to move toward Palk Bay both during the normal times as well as during the times of cyclones 20. The preliminary post tsunami studies available so far on the effect of tsunami on Palk Bay have not contradicted any of the above pre-tsunami conclusions. They have once more affirmed the demand by the scientific community that all the above said issues should be studied in depth before taking up any major project in the area. The SSC Environmental Impact Assessment (EIA) in the light of above findings Chandramohan et al.,16 have calculated the total annual sediment load for this sink as 58.8000 X 106 m3. This sediment load is said to cause a sea depth reduction of 1 cm/year. Marine and riverine sources contribute these sediments. Small rivers draining into Palk Bay in the Sri Lankan and Indian coasts, longshore currents from Bay of Bengal in the north and Gulf of Mannar in the south transport these sediments into the Palk Bay. Sanil Kumar et al., 20 have calculated the net quantum of littoral sediments entering into the Palk Bay from the Nagapattinam coast as 0.095 X 106 m3. The Environmental Impact Assessment (EIA) for SSCP by NEERI has calculated the net annual sediment transport by long shore current and tides in the Adams Bridge area as 00.2657 X 106 m3(Ref 14). The sediment contribution from the rivers is yet to be calculated. These studies indicate that we are yet to pinpoint the sediment source for about 58.4393 X 106 m3 (i.e.99.386%) of the total sedimentation volume as indicated by Chandramohan et al.’s study. The total quantity of spoils that would come from capital dredging is supposed to be 81.5 to 88.5 X 106 m3. The quantum of dredged spoil that would come from maintenance dredging is supposed to be 0.1 X 106 m3 / year. Specific dumpsite has been identified only for 8.5 to 9.5 % of the total dredged spoil. Idea about the nature of the dredged spoil is available presently, only for about 38.5 to 40.5 % of the total dredged spoil. No idea exists at the present time on the nature of the dredged spoil that would be generated for 59.5 to 61.5 % of the total dredged material. We do not know the exact dumpsites for about 90.5 to 91.5 % of the dredged material 17. EIA and the Technical Feasibility Report (TFR) are the two tools based on whose scientific strengths the Ministry of Environment and Forests accepts or rejects a project. The NEERI EIA and TFR for SSCP had ignored the issues of sedimentation, cyclones and tsunami in their entirety. Even the director of NEERI had accepted this in a recent press interview openly. Strangely, MoE&F had chosen to give its clearance for the project even though the project’s EIA and TFR are incomplete. Indian study initiatives on the December 26th tsunami NIO, Goa has given a model of tsunami wave propagation in February 2005. An oceanographic expedition to tsunami-affected areas was mounted on 15 January 2005 utilizing the services of the multidisciplinary ocean research vessel, ORV Sagar Kanya, the flagship of the country involving participation of oceanographers from NCAOR and NIO, Goa and NIO, Regional Centre (RC), Visakhapatnam, NPOL, Kochi and NORINCO, Chennai. It ended on 21 February thus lasting 37 days. Its preliminary report has been published in CURRENT SCIENCE, VOL. 88, NO. 7, 10 APRIL 2005. NIO along with Department of Science & Technology (DST), Department of Ocean Development (DOD), Council of Scientific and Industrial Research (CSIR) and Indian National Science Academy (INSA) had conducted on 21 and 22 January 2005, a brain storming session on the issue of disaster management in the coastal areas with respect to cyclones and tsunamis. Indian and international experts in tsunami, cyclones, oceanography and geology had participated in this session. Following this session, NIO along with the other above said departments had organized a “National Workshop on Formulation of Science Plan for” Coastal Hazard Preparedness” on 18 - 19 February 2005. Various Indian and International experts attended this workshop again. Incidentally, NEERI had sent its representative to attend this workshop. This workshop had noted the following: “India has a long coastline (~7500 km) and a large Exclusive Economic Zone (EEZ) (~2 million sq. km.) that includes two major groups of islands, all of which are susceptible to different coastal hazards. Peninsular India comprises of nine populous states, with a significant component of their economy in some way related to the sea. This includes fishing, shipping, ports and harbors, tourism and allied industries. The last few years have also seen new investment being made in our coastal zone (on the continental shelf and slope) for oil and gas exploration. The investment - over US$ two billion per year by some estimates - involves construction of platforms, pipelines, and other structures. These could eventually become a critical component of the national economy. With these new developments also come new threats: while these offshore structures are vulnerable to storm surges or tsunami or submarine mudslides, they are also a potential source of oil spills, which too constitute a hazard affecting fisheries and coastal environment Engineering solutions for control and remediation are important where and when the cheaper and less intrusive natural methods are ineffective. With exploration for oil gaining momentum, offshore structural engineering is gaining importance. The potential threat to such structures from submarine mudslides necessitates engineering design solutions to mitigate the impact. Since poor quality of construction has been identified as one of the causes of higher fatalities due to natural hazards in India, quantification of these hazards must also lead to better regulations and viable building codes.” However, MoE&F had refused to consider the results of all these research and policy initiatives while rushing a clearance for SSCP. International initiatives in risk assessment There are 3 records of past tsunamis that had affected Palk Bay. They are the tsunamis of 31 december1881, 26 August1883 and 26 June 1941. The 1883 tsunami had been studied in detail by Prof.Byung Ho Choi of the Department of Civil and Environmental Engineering, Sungkyunkwan University, Suwon, Korea. He was here in India this January to study the December 26th tsunami run up. His study along with Prof.Siripong titled "When the Sea Strikes Back: The December 26, 2004 Earthquake Tsunami of the Indian Ocean - Post Runup Survey" is to be presented in the Workshop on Indonesian Ocean Tsunami 2005 and the 13th PAMS/JECSS Meeting to be held at Bali, Indonesia, in 13-15 July 2005. MoE&F should have directed the TPT to consider the implications of all these studies on the long-term stability of the canal. Instead of this, it had issued a clearance for the project in much haste. Conclusion MoE&F is the top environmental regulating body in India. It is responsible for scrutinizing the scientific credentials (with respect to environment) of all the major projects coming up in India. In the case of Sethusamudram Shipping Canal Project, we see this body faltering in its job as a scientifically informed regulator. Steps to correct this flaw should now be undertaken by the PMO, Cabinet Committee and the Planning Commission. Without this corrective step, it is felt, that the project might turn out to be a failure in all its aspects. Such a failure has the potential to cause great hardship to the economy, environment and the social fabric not only of India but also of Sri Lanka. It would also turn out to be a perfect negative example for all the future EIAs in India. The project’s failure might also cost India its honor as a developing nation that has the technological potential to become a developed one by the year 2020. References 1) The Hindu 9 April 2005 2) EPW, 22-28 January 2005, Current Science 2 February, 2005, The New Indian Express 9 March 2005, The New Indian Express 29 March 2005, The Hindu 30 March 2005 3) The Telegraph India, 29 January 2005 4) Dina Thanthi 31 March 2005 5) PTI, 27 December 2004 6) The Hindu 25 March 2005 7) The Hindu 7 April 2005 8) http://www.nio.org 9) The Hindu 10 April 2005 10) For a 3 dimensional model of Palk Bay based on Prof.Sandwell’s (of Scripps Institute of Oceanography) satellite bathymentric data see: http://southindiatsunami.blogspot.com 11) This point is proved by the data on the run-up heights published in: R.K.Chadha, G.Latha, Harry Yeh, Curt Peterson, Toshitama Katada, “The tsunami of the great Sumatra earthquake of M 9.0 on December 2004 – Impact on the east coast of India”, in Current Science, Vol.88, No.8, 25 April 2005 12) The Times of India, JANUARY 14, 2005 13) Dr.Senthil Kumaran, Unpublished Report 14) The Hindu, 22 April 2005, “Marine ecology of Bay of Bengal irrevocably altered by tsunami” 15) NEERI, EIA for Proposed Sethusamudram Shipping Canal Project, May, 2004, p.3.63 16) Chandramohan, P., Jena, B.K., and Sanil Kumar, V., ‘Littoral drift sources and sinks along the Indian coast’, Current Science, Vol. 81, No. 3, 10, 2001, p-295 17) Ramesh, R. ‘Sethusamudram Shipping Canal Project and the unconsidered high risk factors’, at http:\\www.geocities.com\sethushipcanal 18) Jeyanthi, N., “Cyclone Disaster Risk in Coastal Region”, in ‘Cyclone Disaster Management’ National Interactive Workshop held at Tamil Nadu Agricultural University, February 25-26, 2002. 19) Chaudhuri, S., Chattopadhyay, S., ‘Identification of coasts vulnerable for severe Tropical Cyclones - Statistical Evaluation’, Mausam, 55, 3 (July 2004), p. 502-507 20) Sanil Kumar, V., Anand,NM., and Gowthaman,R., ‘Variations in nearshore processes along Nagapattinam coast, India’,Current Science, Vol. 82, No. 11, 2002, p-1381 - 1389 21. 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